It said the aid effort lacked co-ordination, and the United Nations refugee agency needed to provide more effective leadership.

The comments came as two Serb soldiers held as prisoners of war by the US military in Germany were released.

An official with the International Committee of the Red Cross in Hungary said the two men had been flown to the Hungarian capital, Budapest. They were due to be handed over to the Yugoslav authorities later on Tuesday.

The two soldiers were captured in Yugoslavia by the rebel Kosovo Liberation Army, and taken to Albania where they were handed over to the US military.

Search for endgame

The releases coincided with increasing speculation about splits within Nato and an intensification of diplomatic efforts to find a solution.